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    <import namespace="http://fasb.org/srt-types/2026" schemaLocation="https://xbrl.fasb.org/srt/2026/elts/srt-types-2026.xsd" />
    <element id="PTIX_CommonStockPurchaseWarrantMember" name="CommonStockPurchaseWarrantMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_SeriesAConvertiblePreferredStockMember" name="SeriesAConvertiblePreferredStockMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_SeriesBConvertiblePreferredStockMember" name="SeriesBConvertiblePreferredStockMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_SeriesCConvertiblePreferredStockMember" name="SeriesCConvertiblePreferredStockMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_SeriesC1ConvertiblePreferredStockMember" name="SeriesC1ConvertiblePreferredStockMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_SeriesDConvertiblePreferredStockMember" name="SeriesDConvertiblePreferredStockMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_PhytanixBioIncMember" name="PhytanixBioIncMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_SeriesCOnePreferredStockMember" name="SeriesCOnePreferredStockMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_UnwindAgreementMember" name="UnwindAgreementMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_AssembledWorkforceMember" name="AssembledWorkforceMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_PhytanixBioMember" name="PhytanixBioMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_EmployeesMember" name="EmployeesMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_NonEmployeesMember" name="NonEmployeesMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_ResearchAgreementsMember" name="ResearchAgreementsMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_CashInBank" name="CashInBank" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_AccountingAndAuditFees" name="AccountingAndAuditFees" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_DerivativeGainLossOnDerivativeNetAndFairValueAdjustmentOfWarrants" name="DerivativeGainLossOnDerivativeNetAndFairValueAdjustmentOfWarrants" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_ForeignCurrencyExchangeDifferences" name="ForeignCurrencyExchangeDifferences" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_StockIssuedDuringPeriodValuePreferredStockToOfficers" name="StockIssuedDuringPeriodValuePreferredStockToOfficers" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_StockIssuedDuringPeriodSharesPreferredStockToOfficers" name="StockIssuedDuringPeriodSharesPreferredStockToOfficers" nillable="true" xbrli:periodType="duration" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_StockIssuedDuringPeriodValueReverseMerger" name="StockIssuedDuringPeriodValueReverseMerger" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_StockIssuedDuringPeriodSharesReverseMerger" name="StockIssuedDuringPeriodSharesReverseMerger" nillable="true" xbrli:periodType="duration" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_StockIssuedDuringPeriodValueBioPurchase" name="StockIssuedDuringPeriodValueBioPurchase" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_StockIssuedDuringPeriodSharesBioPurchase" name="StockIssuedDuringPeriodSharesBioPurchase" nillable="true" xbrli:periodType="duration" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_StockIssuedDuringPeriodValueWarrantExercise" name="StockIssuedDuringPeriodValueWarrantExercise" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_StockIssuedDuringPeriodSharesWarrantExercise" name="StockIssuedDuringPeriodSharesWarrantExercise" nillable="true" xbrli:periodType="duration" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_StockIssuedDuringPeriodValueOptionExercise" name="StockIssuedDuringPeriodValueOptionExercise" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_RoundingFromReverseSplit" name="RoundingFromReverseSplit" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_RoundingFromReverseSplitShares" name="RoundingFromReverseSplitShares" nillable="true" xbrli:periodType="duration" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_IncreaseDecreaseInValueAddedTaxReceivable" name="IncreaseDecreaseInValueAddedTaxReceivable" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_IncreaseInNotePayableForAcquisitionOfPhytanixBio" name="IncreaseInNotePayableForAcquisitionOfPhytanixBio" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_NetAssetsAcquiredOfPhytanixBioNetOfCashReceived" name="NetAssetsAcquiredOfPhytanixBioNetOfCashReceived" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_WorkingCapitalDeficit" name="WorkingCapitalDeficit" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_ConsiderationOfCash" name="ConsiderationOfCash" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_ReceiptOfCompanyShares" name="ReceiptOfCompanyShares" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_BusinessCombinationSeparatelyRecognizedTransactionsAssets" name="BusinessCombinationSeparatelyRecognizedTransactionsAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_BusinessCombinationSeparatelyRecognizedTransactionsLiabilitiesNetLiabilitiesDeconsolidated" name="BusinessCombinationSeparatelyRecognizedTransactionsLiabilitiesNetLiabilitiesDeconsolidated" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_BusinessCombinationSeparatelyRecognizedTransactionsLiabilitiesNetDeconsolidated" name="BusinessCombinationSeparatelyRecognizedTransactionsLiabilitiesNetDeconsolidated" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_BusinessCombinationSeparatelyRecognizedTransactionsNetGainAndLosses" name="BusinessCombinationSeparatelyRecognizedTransactionsNetGainAndLosses" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_ResearchAndDevelopmentCurrent" name="ResearchAndDevelopmentCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_LegalCurrent" name="LegalCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_GeneralAndAdministrativeCurrent" name="GeneralAndAdministrativeCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_AccruedResearchAndDevelopment" name="AccruedResearchAndDevelopment" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualGranted" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualGranted" nillable="true" xbrli:periodType="duration" type="xbrli:durationItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingWeightedAverageExercisePrice" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingWeightedAverageExercisePrice" nillable="true" xbrli:periodType="instant" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingWeightedAverageRemainingContractualTerm" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingWeightedAverageRemainingContractualTerm" nillable="true" xbrli:periodType="duration" type="xbrli:durationItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGrantsInPeriodWeightedAverageExercisePrice" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGrantsInPeriodWeightedAverageExercisePrice" nillable="true" xbrli:periodType="duration" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExpirationsInPeriodWeightedAverageExercisePrice" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExpirationsInPeriodWeightedAverageExercisePrice" nillable="true" xbrli:periodType="duration" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisedInPeriodWeightedAverageExercisePrice" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisedInPeriodWeightedAverageExercisePrice" nillable="true" xbrli:periodType="duration" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_PreferredStockStatedValue" name="PreferredStockStatedValue" nillable="true" xbrli:periodType="instant" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsNonOptionsAggregateIntrinsicValueOutstanding" name="SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsNonOptionsAggregateIntrinsicValueOutstanding" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_RoyaltyPaymentPercentage" name="RoyaltyPaymentPercentage" nillable="true" xbrli:periodType="instant" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_UpFrontSubLicenseFeesPercentage" name="UpFrontSubLicenseFeesPercentage" nillable="true" xbrli:periodType="instant" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="PTIX_RoyaltyPaymentOnBehalfOfSublicenseePercentage" name="RoyaltyPaymentOnBehalfOfSublicenseePercentage" nillable="true" xbrli:periodType="instant" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
</schema>
